It has always been desirable to improve the antibacterial properties and biocompatibility of certain objects. In particular the desire is to improve antibacterial properties while maintaining other useful properties such as biocompatibility. Over the past 35 years, polymer matrices such as hydrogels have been extremely useful in biomedical and pharmaceutical applications, mainly due to their high water content and rubbery nature which is similar to natural tissue, as well as due to their biocompatibility. Also polymer matrices which are not hydrogels are used within many biomedical and pharmaceutical applications, and it is desired to increase the biocompatibility and antimicrobial properties of those. Examples of known antimicrobial and biocompatible objects for different purposes are outlined below.
U.S. Pat. No. 6,224,983, U.S. Pat. No. 5,965,204, U.S. Pat. No. 5,747,178, U.S. Pat. No. 5,395,651, and U.S. Pat. No. 5,320,908 to Ad Tech Holdings Ltd. disclose articles and methods for preparing articles comprising a layer of silver stabilised by exposure to one or more salts of one or more metals chosen from platinum, palladium, rhodium, iridium, ruthenium and osmium. Examples of the substrate include latex, polystyrene, polyester, polyvinylchloride, polyurethane, ABS polymers, polycarbonate, polyamide, polytetrafluoroethylene, polyimide or synthetic rubber. A latex catheter coated with hydrogel which is further coated with a silver layer is also disclosed.
WO 2005/073289 to Qinetiq Nanomaterials Ltd. discloses fibres made of a polymer composite comprising metal nanoparticles. It is stated that many metals have antimicrobial effects. Antimicrobial fibres are mentioned. One example is a hydrophilic fibre used in antimicrobial wound dressings. Fibres with antimicrobial properties can comprise Ag, Au, Pt, Pd, Ir, Sn, Cu, Sb, Bi or Zn or any combination thereof.
U.S. Pat. No. 6,716,895 to C. R. Bard, Inc. discloses polymer compositions containing colloids of salts of one or more oligodynamic metals. A salt of an oligodynamic metal is reacted with another salt to form a less soluble salt which precipitates as a fine colloid. Examples of metals are silver, platinum, gold, zinc, copper, cerium, gallium, and osmium. An article to be coated is then contacted with a suspension of the poorly soluble colloids. The colloids in the polymer coating can comprise metals salts or metal oxides of oligodynamic metals or a combination thereof.
“Gold and gold-palladium coated polypropylene grafts in a S. epidermidis wound infection model” by Saygun O, Agalar C, Aydinuraz K, Agalar F, Daphan C, Saygun M, Ceken S, Akkus A, and Denkbas E B in J. Surg. Res., 2006 March 131(1):73-9, discloses polypropylene coated with gold and palladium-gold by magnetron sputtering.